Artificial tooth replacements are used in prosthetic dentistry to improve the appearance and/or functionality of a patient's teeth. A common artificial tooth replacement comprises a dental implant that is anchored within the bone, an abutment fastened to the implant with a screw, and a functional and aesthetic tooth replacement (a crown) positioned on the abutment. The abutment serves as the interface between the implant and the crown.
Traditionally, both the implant and the abutment are formed of metal (e.g., titanium or gold alloys), and the crown is often made entirely of ceramic. However, metal abutments have certain aesthetic drawbacks. First, where a patient's soft tissue (or gum tissue) are thinner, for example in the anterior, or front, region of the mouth, the gray color of the metal abutment can be seen through the soft tissue. In patients where soft tissue recedes below the level of the abutment, a portion of the metal abutment may be exposed above the soft tissue. Further, the metal abutment may sometimes be visible through an all-ceramic crown.
To improve the aesthetics of the tooth replacement, ceramics have been contemplated as alternative materials for the formation of abutments. Unlike metals, certain ceramics closely replicate the natural tooth in appearance—i.e., color and translucency. Ceramics, however, are much more brittle than titanium, such that it is challenging to design small shapes that resist breakage. Creation of a structurally sound ceramic dental abutment therefore presents many challenges.